Rhoxalpharma had appealed against a decision in the Federal Court in December 2000 in favour of AstraZeneca after alleging that its omeprazole product, developed by Andrx, would not infringe AstraZeneca's formulation patents for Losec®.

The Appeal Division agreed with the Federal Court finding that RhoxalPharma's allegation of non-infringement was not justified and therefore prohibited the Minister of Health from giving RhoxalPharma marketing approval for the generic product until expiry of the formulation patents in June 2009. Omeprazole is the active ingredient in Losec®.

In Canada, AstraZeneca has several patents covering Losec®, among those are patents for salts, formulations and uses, and intends to fully enforce its patent rights. These patents expire between 2007 and 2014.